By Arthur Middleton Hughes
We live in a universe in which there are hundreds of billions of stars located in billions of galaxies. Most of these stars have planets whizzing around them. None of these planets, save ours, have intelligent life. By intelligent life, I mean people like ourselves who can think, write and read and do all the intelligent things that we do on earth.
In the first place, how do I know this to be true, and in the second place, what does this mean for our lives today? Read John Gribbin’s Alone in the Universe (John Wiley & Sons 2011). He takes the reader through the standard argument: there are so many billions of stars and planets that there is just bound to be at least one with intelligent life on it like ours. There isn’t. In the first place, most stars are too big or too small to have a planet in the “habitable zone”: not too hot and not too cold. There is undoubtedly life on millions, if not billions of planets. But most such life is like early life on earth: creatures swimming in the oceans, or growing, or wandering on land. What is missing is intelligent life.
What makes this planet unique is the moon. Another planet the size of Mars crashed into the earth 4.4 billion years ago, melted the surface, and in the process threw off enough material to form the Moon. The Moon acts as a gravitational stabilizer and provides the tides, the tilt and plate tectonics. The tides are why sea life was washed up on land and learned to grow or live there. The gravitational stability keeps the earth from rolling over periodically with the North Pole, for example, pointing at the sun and the equator freezing over. Most other planets roll over from time to time. Were this to happen to us, it is highly unlikely that life like ours would have or could have evolved.
The effect of plate tectonics is also central to the development of intelligent life. Plate tectonics in planets is “neither mandatory nor common” according to David Stevenson of Caltech. Tectonic activity creates change: it thrusts up mountains, and changes climates. Changing climates, particularly ice ages, are why human beings came to be.
For the first 2.4 billion years of the earth’s existence there was life on earth. But the life consisted of simple calls called prokaryotes which are little bags of jelly containing the chemicals of life such as DNA and proteins. Then about 570 million years ago the first creatures with shells began to appear with DNA which eventually led to life on land — plants and animals of many kinds, including birds, mammals and dinosaurs. The dinosaurs were wiped out by an asteroid that landed in the Gulf of Mexico 65 million years ago, allowing mammals to begin their population of the earth.
It wasn’t until four million years ago that a species of African woodland ape gained adaptability and intelligence. This happened because the continents shifted towards the poles. The earth cooled and much of the ocean’s water became ice. Rainfall dried up, and the trees that the African apes lived in died out. Those apes which didn’t die had to live by their wits – becoming gradually smarter. There were five ice ages each about 100,000 years long with Interglacials each about 10,000 years long. When each ice age ended, the surviving apes were the fittest – best suited to the new way of life. This only happened in Africa. The apes of South America did not benefit from the ice ages because the trees did not die. It is estimated that all the human beings alive in the world today are descended from a population of less than a thousand early humans living in Africa.
So what are the chances that some other planet whizzing around some other star in the universe would have a similar experience leading to very smart chimpanzees like us? As you can see, the chances are zero. We are alone.
What does this mean for our life today? In the first place, we can stop listening for transmissions from outer space. There have been none, and will be none. There are no other intelligent beings anywhere in the universe. Second, we will not last forever. Our civilization today is based on the burning of coal, oil and natural gas. These fossil fuels were created between 360 and 280 million years ago in the cool swampy environment named the Carboniferous period.
Since we discovered these resources – coal a few thousand years ago, and oil and gas only 150 years ago—we have been using them up at a tremendous rate. When they are gone, they will be gone forever. We can continue our high tech life only by using nuclear power – supplemented by wind and solar. But how long will our civilization last? Eventually, of course, the sun will die out and wipe out the earth. Before that the moon, which is drifting away from the earth by 4 cm per year, will become too far away to provide the stability that it does now, and we will all perish. Earlier than that, another asteroid may hit the earth and kill everyone. We might prevent that by space research—finding the eventual paths of the millions of potential asteroids and using space rockets to move the dangerous ones out of the trajectory of the earth.
But, one way or the other, all of us and our civilization will come to an end. When that does happen, there will be no one to mourn us. There will be nobody to dig through the ruins and discover that here, once, there were very intelligent people who built roads, skyscrapers, jet planes, and the internet—who wrote books, made TV shows and movies, fell in love and had families. We dig through the ruins of ancient Egypt, Greece, Rome and China. No one will be able to do that with our civilization – because there will be no people to do that.
As we live our rapid paced life today, it is important to realize that we are alone and unique. We are a tiny blip in the 13.7 billion years that the universe has existed. We should make the most of what we have, because, eventually there will be no tomorrow.